IG 



TIMIJEB PINES OP THE SOUTHERN UNITKIJ STATES. 



Ill any oue tree the wood is lighter and weaker as we [lass Ironi ihe l)asc to the top. This is 

 true of every tree and of iiH four species. The decrease in weight and strength is most prouounced 

 in the first 20 feet from the stuni]) and },fr<iws snialhr npward. (See fig. 1.) 



49.6 



W 20 30 40 



Feet from Stump. 



Fio. 1. — Diat;riiin Mhnwiii^ variation c»r wL-ii;htwith lioight of free. 



This great dilt'erence in weiglit and strength between butt and top linds exjdanatiou in the 

 relative width of the sunimerwood. Since the specific weight of the dark summerwood baud in 

 eaeli ring is in thrifty growth from 0.!tO to 1. wliile that of the springwood is oidy about M), the 

 relative amount of summerwood lurnislies altogether the most delieate and accurate measure of 

 these ditterences of weight as well as strength, and heiu'c is the surest criterion for ocular inspection 

 of (piality, especially since this relation is free from the disturbing influence of both resin and 

 moisture contents of the wood, so conspicuous in weigiit determinations. 



The following figures .show the distribution of the summerwood in a single tree of Longleaf 

 Pine, as an example of this relation : 



At Ibc stump 



32 feet from stiiiiiii 

 87 feet from stump 



In tlielO 



."""'■" rings Noa. 'Averaeefor Specific 

 o?fe'bTrk. 1«1'?.»« e""'"^"". weight. 



from barl£. 



Per cent. \ Per cent. 



37 ' 52 



25 38 



16 37 



Per cent. 

 50 



33 ' 



0.73 

 .59 

 .55 



